Navigating Towards Sustainability: Alternative Fueling in Marine Transportation
By: Cam LaRocco | On: July 18, 2024
The need to decarbonize the marine sector has driven efforts towards developing green fuels. With maritime global shipping accounting for nearly 3% of worldwide CO2 emissions, the maritime industry faces increasing pressure to reduce its environmental footprint. While currently dominant, traditional fossil fuels are finite and contribute significantly to pollution and climate change. In this article, we explore the pros and cons of 5 different alternative fueling options for marine transport.
1. Liquified Natural Gas (LNG)
LNG is natural gas that has been cooled to a liquid state, making it economical to store and transport. Large quantities are typically transported through cryogenic tankers, otherwise known as LNG carriers. Lesser quantities can be transported in smaller ISO-compliant containers, which can be placed on ships or trucks.
LNG is a suitable fuel for marine vessels and has comparably lower greenhouse gas emissions than its conventional fuel counterparts. From a commercial standpoint, LNG fueling systems can positively impact overall cost-effectiveness despite the initial investment required.
Despite these benefits, risks are associated with this form of alternative fuel if not stored or handled properly in compliance with stringent requirements. LNG is predominately made up of methane (a colorless, odorless, and flammable greenhouse gas). Deficiencies within fueling systems may cause unburned methane to escape into the atmosphere and further contribute to unwanted emissions.
2. Methanol
Methanol is a colorless, volatile liquid chemical with a slightly sweet odor. Methanol can be produced from natural gas, coal, biomass, or CO2.
Advantages of using methanol as an alternative fuel source include lower production costs and emissions relative to other alternative fuels, improved safety due to lower risk of flammability, and increased energy security since it can be manufactured from various domestic carbon-based feedstocks.
A potential downside for methanol as an alternative fuel is that it requires modifications to existing engines and vessel infrastructure. While methanol burns more cleanly than fuel oil environment, it induces significantly greater engine wear compared to fuel oil, which may affect engine operation and durability.
3. Ammonia
Ammonia is a colorless gas with a pungent odor an is considered one of the most hazardous chemicals utilized by the farming and agriculture industries. It is commonly used in various industrial applications, including as a refrigerant, in fertilizers, and as a potential marine fuel. It is a promising alternative fuel due to its zero carbon emissions when combusted and its low cost compared to other alternative fuels. Ammonia can also be produced using renewable energy sources, making it a sustainable option.
One of the most notable benefits of using ammonia for alternative fueling is that it doesn’t produce any CO2 emissions when combusted in a vessel engine. Fortescue has recently successfully conducted the world’s first use of ammonia as an alternative marine fuel.
However, there are safety concerns regarding proper handling of this extremely toxic chemical. Ammonia is often stored and transported under higher pressures and severe side effects may occur if a transfer system experiences a failure and direct exposure occurs. Ammonia exposure has the potential to cause chronic respiratory issues, loss of vision, severe skin burns, or even death if not handled properly. There are ongoing efforts to develop safe and efficient systems for ammonia usage in the maritime industry.
4. Biofuels
Marine biofuels are renewable energy sources derived from biological materials, providing a cleaner alternative to conventional fossil fuels. The main types of biofuels used in the marine industry include biodiesel and bioethanol.
Biodiesel: Produced through transesterification of vegetable oils or animal fats, biodiesel is a direct replacement for conventional marine diesel.
Bioethanol: Created through the fermentation of sugars found in crops like corn and sugarcane, bioethanol can be blended with gasoline for marine applications.
Biofuels are produced using various raw materials, including algae, waste oils, and agricultural residues. Algae, in particular, is a highly efficient biofuel source due to its rapid growth rate and high lipid content, which can be converted into fuel.
Biodiesels have a higher degradation potential and are, therefore, more corrosive than traditional diesel fuels. Furthermore, microbial growth and excessive sludge formation can lead to fuel contamination, clogged or fouled equipment, and even engine failure.
5. Synthetic Fuels (Electrofuels or e-Fuels)
Synthetic fuels are produced from renewable electricity and captured CO2, often referred to as e-fuels. Green hydrogen is the cornerstone of all types of e-fuels—which can be either a liquid or gas.
Some synthetic fuels are considered low-carbon, while others provide a zero-carbon option for ships, such as e-ammonia and e-hydrogen. These carbon-free fuels, once produced at scale, could enable ship owners and operators to significantly reduce their fleets’ environmental footprints. Additionally, e-fuels can be used in existing engines without the need for extensive modifications or infrastructure upgrades.
However, e-fuels typically have higher production costs and involve energy-intensive manufacturing processes. Roughly 60 % of the cost of producing synthetic fuels is spent on the renewable electricity needed to extract the hydrogen via electrolysis. This method offers a sustainable and viable alternative to traditional fossil fuels, especially for long-haul shipping.
Conclusion
Each of these alternatives has its own set of benefits and challenges, and the suitability of each option can vary depending on specific marine applications and regional regulations. The future of marine fuels will likely involve a combination of these technologies to achieve the industry’s sustainability goals. When transferring these fuels through a flexible metal hose, grade 316L stainless steel is typically recommended due to its resistance to biofuels, temperature extremes, and saltwater environments. Dock hoses may need to be tested and marked according to Coast Guard requirements as per the Code of Federal Regulations (CFR). It is recommended to check with the local authorities to verify dock hose testing and marking requirements.
Alternative fuel sources offer a promising path towards more sustainable and environmentally friendly maritime transportation. By reducing carbon emissions, utilizing renewable resources, and fostering positive environmental impacts, alternative fuels represent a significant step forward for the industry.
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Fortescue. “World’s First Use of Ammonia as a Marine Fuel in a Dual-Fueled Ammonia Powered Vessel in the Port of Singapore.” fortescue.com
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